Surgical bone preparation instrument and assembly comprising such an instrument

ABSTRACT

This surgical bone preparation instrument ( 1 ) comprises a main body ( 5 ) terminated by a contacting surface ( 50 ) adapted to abut on a bone (B), and a sliding body ( 7 ) equipped with a cutting element ( 3 ) and which is movable in translation with respect to the main body ( 5 ). The bone preparation instrument ( 1 ) includes a cutting depth control ring ( 11 ) that is adjustable by a single hand, which forms an abutment surface ( 110 ) against the movement of one of the main body ( 5 ) and the sliding body ( 7 ) when the sliding body ( 7 ) reaches an adjusted cutting depth (D) corresponding to an adjustment position of the control ring ( 11 ).

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 C.F.R. § 1.57.

BACKGROUND OF THE INVENTION Field of the Invention

The invention concerns a surgical bone preparation instrument and asurgical bone preparation assembly comprising such a surgical bonepreparation instrument.

Description of the Related Art

The preparation of a surgical articulation replacement operation needsperforming bone reaming to prepare the glenoid bone. This preparationconsists of creating a space for receiving the implant. Such reamingmust be done with a precise reaming depth determined on the basis of thefeatures of the implant and the features of the bone of the patient.

To ensure that the reaming operation is done with the correct reamingdepth, various techniques are already used. U.S. Pat. No. 6,277,121provides a stop member mounted on a reaming instrument and whoseposition along the reaming instrument can be modified as a function ofthe required reaming depth. The stop member comprises a surface whichabuts against a specific bushing attached to the bone when the desiredreaming depth is reached.

Such technique needs further instruments to ensure that the desiredreaming depth is correctly obtained.

SUMMARY OF THE INVENTION

The aim of the invention is to provide a new surgical bone preparationinstrument, which allows controlling the reaming depth with theinstrument itself.

To this end, the invention concerns a surgical bone preparationinstrument comprising a main body terminated by a contacting surfaceadapted to abut on a bone, and a sliding body equipped with a cuttingelement and which is movable in translation with respect to the mainbody, wherein the bone preparation instrument includes a cutting depthcontrol ring that is adjustable by a single hand, which forms anabutment surface against the movement of one of the main body and thesliding body when the sliding body reaches an adjusted cutting depthcorresponding to an adjustment position of the control ring.

Thanks to the invention, the reaming depth can be controlled easily bysetting an adjustment member of the instrument, which limits therelative translation of the main body and the sliding body of theinstrument. The control of the reaming depth is therefore obtained witha simple blocking principle, and without the need of other instrument.

According to further aspects of the invention which are advantageous butnot compulsory, such a surgical bone preparation instrument may alsoinclude one or several of the following features:

-   -   The cutting depth is adjusted by rotating the control ring to        adjust the axial position of the abutment surface of the control        ring with respect to the sliding body.    -   The cutting depth control ring is adjustable by a single action.    -   The main body comprises a radial pin extending in an oblong hole        of the sliding body, the abutment surface of the cutting depth        control ring acting as an axial stop on the radial pin.    -   The control ring comprises markings for checking the position of        the control ring.    -   The cutting depth control ring is mounted on the sliding body        with a screw mounting, and the cutting depth is adjusted by        screwing or unscrewing the control ring to adjust its axial        position on the sliding body.    -   The cutting depth control ring is mounted movable in rotation        and fixed in translation on the sliding body and spring-biased        by a spring with respect to the main body, and the abutment        surface of the cutting depth control ring has a profile defining        different axial lengths of the cutting depth control ring.    -   The spring urges the contacting surface of the main body against        the bone during cutting.    -   The cutting depth control ring comprises a proximal axial        surface having notches distributed circumferentially for        positioning according to various depths corresponding to the        different axial lengths of the control ring, and the sliding        body comprises a protrusion adapted to insert in the notches of        the proximal axial surface to lock the angular position of the        control ring under action of the spring.    -   The sliding body is arranged radially inside a cylindrical        portion of the main body, the contacting surface of the main        body is arranged radially inside the cutting element, and the        sliding body comprises longitudinal slits receiving in sliding        manner attachment members of the main body which connect the        contacting surface to the cylindrical portion.    -   The cutting element comprises a central aperture through which        the contacting surface of the main body protrudes.    -   The sliding body can be dismounted from the main body.    -   The adjusted cutting depth is pre-planned.    -   The main body and the sliding body comprise a bore for insertion        of a reference pin adapted to be fixed to the bone in order to        guide the bone preparation instrument.

The invention also concerns a surgical bone preparation assemblycomprising a surgical bone preparation instrument according to any ofthe preceding claims, wherein it comprises at least one reference pinadapted to be fixed to a bone to be prepared of a patient in order toguide the bone preparation instrument, and wherein it comprises apatient-specific positioning tool for positioning the reference pin onthe bone.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in correspondence with the annexedfigures, as an illustrative example. In the annexed figures:

FIG. 1 is a perspective view of a surgical bone preparation instrumentaccording to a first embodiment of the invention, a cutting elementbeing omitted;

FIG. 2 is a partially exploded perspective view of the instrument ofFIG. 1 with the cutting element being shown;

FIG. 3 is a sectional view of the instrument of FIGS. 1 and 2, along alongitudinal plane comprising a central axis of the instrument, thecutting element being omitted;

FIG. 4 is a perspective view of a sliding body of the instrument ofFIGS. 1 to 3;

FIG. 5 is a side view of a control ring of the instrument of FIGS. 1 to3;

FIG. 6 is a sectional view of the instrument of FIGS. 1 to 3, prior to acutting step;

FIG. 7 is a sectional view similar to FIG. 6, at the end of a cuttingstep;

FIG. 8 is a perspective view of the instrument of FIG. 1, of a referencepin on which the instrument is mounted, and a bone in which thereference pin is attached, the instrument being represented prior to acutting step;

FIG. 9 is a view similar to FIG. 8, at the end of the cutting step;

FIG. 10 is a perspective view of the bone at the end of the cuttingstep;

FIG. 11 is a sectional view of a surgical bone preparation instrumentaccording to a second embodiment of the invention, along a longitudinalplane comprising a central axis of the instrument.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 to 3 represent a surgical bone preparation instrument 1 whichextends along a central axis X. The axis X also corresponds to thetranslation axis of the instrument 1 during the reaming of a glenoidsurface for a bone preparation prior to a surgical articulationreplacement operation.

The instrument 1 comprises a reaming tool 3 which is fixed on theinstrument 1. The central axis X is also the rotation axis of thereaming tool 3.

The instrument 1 comprises a main body 5 terminated by a contactingsurface 50 adapted to abut on a bone B which is to be prepared using theinstrument 1. The contacting surface 50 is substantially orthogonal tothe central axis X.

In what follows, the term “distal” denotes an element of the instrument1 located on the side of the contacting surface 50 or a surface orientedtowards the contacting surface 50. The term “proximal” denotes anelement of the instrument 1 located opposite the contacting surface 50or a surface oriented opposite to the contacting surface 50. The forwarddirection is oriented towards the distal side.

The terms “axial” or “axially” and “radial” or “radially” referrespectively to directions parallel and transverse to the central axisX. An axial surface is a surface orthogonal to the central axis X, whilea radial surface is a cylindrical surface centered on the central axisX.

The main body 5 is hollow and forms an inner cavity 52 in which isinserted a sliding body 7, that is equipped with the reaming tool 3.Alternatively, the sliding body 7 may be equipped with another type ofcutting element. The sliding body 7 is movable in translation withrespect to the main body 5 along the central axis X.

The instrument 1 also comprises an elongated handle 9 that extendsaxially from the sliding body 7. The handle 9 is covered by a perforatedsleeve 90.

During the reaming of a surface of the bone B, the surface 50 abuts thebone B and remains stationary, while the sliding body 7 moves along theaxis X with respect to the main body 5 and progressively reams the boneB. To control the reaming depth, the axial displacement of the slidingbody 7 with respect to the main body 5 must be limited to a predefinedvalue corresponding to the desired reaming depth.

To this end, the instrument 1 comprises a cutting depth control ring 11.The control ring 11 is adjustable by a single hand. The control ring 11forms an abutment surface against the axial movement of one of the mainbody 5 and the sliding body 7 when the sliding body 7 reaches anadjusted cutting depth corresponding to an adjustment position of thecontrol ring 11.

The control ring 11 is rotatable with respect to the main body 5 and thesliding body 7, and movable in translation with respect to the main body5 so as to be set to the adjustment position corresponding to thedesired cutting depth. The control ring 11 comprises a distal surface110 that forms the abutment surface. The main body 5 comprises a radialpin 52 which is inserted in a through oblong hole 70 of the sliding body7. The oblong hole 70 has a largest dimension oriented parallel to thecentral axis X, meaning that the pin 52 is free to move in translationin the oblong hole 70 along the axis X. The pin 52 is also inserted intotwo opposed holes 54 of the main body 5. The holes 54 have a shapecorresponding to the outer shape of the pin 52, meaning that the pin 52is stationary in translation along the central axis X with respect tothe main body 5. The pin 52 comprises a radial protrusion 52 a whichprotrudes from an outer peripheral surface 55 of the main body 5. Theprotrusion 52 a faces the distal surface 110 of the control ring 11 andacts as a stop to block the sliding body 7 to the depth corresponding tothe adjusted position of the control ring 11.

The control ring 11 is mounted on the sliding body 7 with a spring 13that urges the control ring 11 towards the proximal side of theinstrument 1. The spring 13 is mounted between an axial surface 56 ofthe main body 5, and an inner axial surface 112 of the control ring 11.

The control ring 11 comprises a proximal axial surface 114 havingnotches 114 a which are distributed circumferentially for positioningthe control ring 11 according to various adjusted positions definingcutting depths which correspond to different axial lengths of thecontrol ring 11. As represented on FIG. 5, the various notches 114 adefine, with respect to the abutting surface 110, various axial lengthsof the control ring 11 depending on their position around the centralaxis X. The abutting surface 110 has a substantially helical profiledefining increasing cutting depths from a first adjusted position “0”which defines a zero cutting depth, to a last adjusted position “4”,which defines a maximal cutting depth. The control ring 11 comprisesengraved markings or other types of markings showing the cutting depthassociated with each of the notches 114 a. The minimal cutting depth “0”corresponds to a maximal axial length LM of the control ring 11, whilethe maximal cutting depth “4” corresponds to a minimal axial length Lmof the control ring 11.

The markings of the control ring 11 can be different, designingdifferent depths and different incremental values. The positioning ofthe notches 114 a along the circumferential direction of the controlring 11, the preset depths of the control ring 11 and the maximal andminimal axial lengths LM and Lm can be different, and may be modifieddepending on the types of surgical procedures and patient geometries.

The sliding body 7 comprises a protrusion 74 located at the proximalside of the sliding body 7 and oriented towards the distal side, whichhas a shape complementary to the shape of the notches 114 a. Theprotrusion 74 is adapted to insert in the notches 114 a to lock theangular position of the control ring 1 under action of the spring 13.When the protrusion 74 is engaged in one of the notches 114 a, the axialposition of the control ring 11 is locked by the abutment between theprotrusion 74 and the notch 114 a under action of the spring 13. At thesame time, the round shape of the protrusion 74 and the notch 114 aprevents relative rotation of the control ring 11 with respect to thesliding body 7, locking the adjusted position of the control ring 11 andthe desired cutting depth. If the desired cutting depth is to bemodified, the control ring 11 has to be pushed forward by hand torelease the notch 114 a from the protrusion 74, then turn the controlring 11 around the central axis X to position the control ring 11 sothat the protrusion 74 is aligned with another of the notches 114 aaccording to the new desired cutting depth. This can be done with asingle movement of two fingers of a single hand. The adjustment of thecontrol ring 11 needs only one action. In other words, the surgeon onlyneeds to place its fingers on the control ring 11 and make the movement.There is no need for displacing the fingers in another position toperform another movement.

Simultaneously, the spring 13 also pushes forward the main body 5 byurging the main body 5 away from the control ring 11, which is in fixedaxial relationship with the sliding body 7. The spring 13 thereforeurges the contacting surface 50 against the bone B during cutting.

The sliding body 7 is arranged radially inside a cylindrical portion 56of the main body 5. The contacting surface 50 is arranged radiallyinside the cutting element 3, the link between the cylindrical portion56 and the contacting surface 50 is made by attachment members 58 thatare received in longitudinal slits 76 of the sliding body 7. The slits76 extend on the distal side of the sliding body 7 and allow the axialtranslation of the connecting members 58 along the axis X. The cuttingelement 3 comprises a central aperture 30 through which the contactingsurface 5 protrudes.

The sliding body 7 comprises an inner channel 60 for insertion of areference pin 15 adapted to be fixed to the bone B in order to guide theinstrument 1 during cutting. The channel 60 extends through the slidingbody 7 and is continued by a channel 92 provided in the handle 9. Afront portion 94 of the handle 9 is inserted through a bore 52 b of thepin 52. The entire instrument 1 is therefore free to translate axiallywith respect to the reference pin 15 during cutting.

The reference pin 15 and the instrument 1 form a surgical bonepreparation assembly. The assembly may also include a non-shown tool forpositioning or guiding the reference pin 15 on the bone B. This tool maybe patient specific and built to correspond to the bone supports of thepatient. The shape of the tool may be obtained with a planning software.

The working principle of the invention will now be explained in detailwith reference to FIGS. 6, 7, 8 and 9. In a first configurationrepresented on FIGS. 6 and 8, the instrument 1 is positioned away fromthe bone B before the beginning of the cutting operation. The instrument1 is mounted on the reference pin 15. The control ring 11 is maneuveredto set the cutting depth to the maximal value or another value byrotating the control ring 11 and releasing it. Under action of thespring 13, the notch 114 a associated with the maximal cutting depth isinserted on the protrusion 74. The maximal cutting depth is marked by amarking “4” on the outer surface of the control ring 1. In thisconfiguration, the main body 5 is completely pushed forward by thespring 13. The protrusion 52 a is therefore located away from thesurface 110, and the contacting surface 50 protrudes from the blades 32of the cutting element 3.

When cutting begins, the instrument 1 is pushed along the axis X towardsthe bone B and is guided by the reference pin 15. The contacting surface50 abuts against the bone B, and the instrument 1 is pushed furthertowards the bone B so that the cutting element 3 cuts the bone B aroundthe contacting surface 50. The sliding body 7 therefore translates withrespect to the main body 5, the spring 13 is compressed and the pin 52is moved with respect to the sliding body 7 towards the proximal side,in the direction of the surface 110. The movement of the pin 52 isallowed by the free space provided by the oblong hole 70.

As represented on FIGS. 7 and 9, once the desired cutting depth D isobtained, the protrusion 52 a abuts against the surface 110, preventingthe sliding body 7 from translating further with respect to the mainbody 5. The surface of the bone B has been reamed, leaving a bone remain17 having the shape of the inner space 30 of the cutting element 3. Theheight extending between the reamed surface 19 and the former bonesurface 21, that is represented in dotted lines on FIG. 10 and ispresent on the bone remain 17, corresponds to the cutting depth D.

The cutting depth is preferably pre-planned, for example using imagingsuch as X-rays, MM or CT scans, and/or using a pre-planning software forvisualizing the bone in three dimensions. The software used forproviding a tool for positioning the reference pin 15 may be used.

According to an optional embodiment, the sliding body 7 can bedismounted from the main body 5. The handle 9 can be separated from thesliding body 7 by unscrewing. With the front portion 94 being extractedfrom the bore 52 b, the pin 52 can be radially removed from the slidingbody 7. The sliding body 7 can then be axially dismounted from the mainbody 5.

A second embodiment of the invention is represented on FIG. 11. In thisembodiment, elements similar to the embodiments of FIGS. 1 to 9 have thesame references and work in the same way.

In the embodiment of FIG. 11, the control ring 11 comprises an innerthread 116 and the sliding body 7 comprises an outer thread 76. Thecontrol ring 11 is mounted on the sliding body 7 with a screw mounting.By unscrewing or screwing the control ring on the sliding body 7, theaxial position of the control ring 11 on the sliding body 7 can beadjusted. The screwing or unscrewing for adjusting the position of thecontrol ring 11 can be easily made in a single movement with twofingers, in a single action.

The abutment surface 110 is, in this case, perpendicular to the centralaxis X, and the cutting depth is adjusted by modifying the axialposition of the control ring 11 instead of modifying the angularposition of the control ring in the first embodiment.

In a similar principle, the instrument of FIG. 11 comprises a radial pin52 that is mounted fixed in translation with respect to the main body 5,and free to translate in an oblong hole 70 of the sliding body 7. Whenthe desired cutting depth is reached, the pin 52 abuts against thesurface 110, preventing the instrument from reaming the bone B to adepth superior to the adjusted depth.

The invention also concerns a surgical articulation replacement method,comprising at least a step consisting of making a bone preparation witha surgical bone preparation instrument, said bone preparation consistingof making a cut of a specific required cutting depth, wherein thespecific required cutting depth of the bone preparation is pre-planned.

The invention also concerns a surgical articulation replacement method,in which the specific required cutting depth of the bone preparation ispre-planned using a pre-planning software.

What is claimed is:
 1. Surgical bone preparation instrument comprising amain body terminated by a contacting surface adapted to abut on a boneand to remain stationary thereon, and a sliding body equipped with acutting element, wherein the cutting element and sliding body aremovable in translation, axially along a central axis of the bonepreparation instrument, with respect to the main body and the contactingsurface when the main body stationarily abuts a bone through thecontacting surface, wherein the bone preparation instrument includes acutting depth control ring that is separate from the main body and thesliding body, wherein the cutting depth control ring forms an abutmentsurface against the movement of one of the main body and the slidingbody when the sliding body reaches an adjusted cutting depthcorresponding to an adjustment position of the control ring, wherein theabutment surface has a substantially helical profile defining increasingcutting depths.
 2. Surgical bone preparation instrument according toclaim 1, wherein the cutting depth is adjusted by rotating the controlring to adjust an axial position of the helical profile of the abutmentsurface of the control ring with respect to the sliding body. 3.Surgical bone preparation instrument according to claim 1, wherein thecutting depth control ring is adjustable by a single action.
 4. Surgicalbone preparation instrument according to claim 1, wherein the main bodycomprises a radial pin extending in an oblong hole of the sliding body,the abutment surface of the cutting depth control ring acting as anaxial stop on the radial pin.
 5. Surgical bone preparation instrumentaccording to claim 1, wherein the control ring comprises markings forchecking the position of the control ring.
 6. Surgical bone preparationinstrument according to claim 1, wherein: the cutting depth control ringis mounted on the sliding body with a screw mounting, and the cuttingdepth is adjusted by screwing or unscrewing the control ring to adjustits axial position on the sliding body.
 7. Surgical bone preparationinstrument according to claim 1, wherein: the cutting depth control ringis mounted movable in rotation and fixed in translation on the slidingbody and spring-biased by a spring with respect to the main body alongthe central axis of the surgical bone preparation instrument, and theabutment surface of the cutting depth control ring has a profiledefining different axial lengths of the cutting depth control ring. 8.Surgical bone preparation instrument according to claim 7, wherein thespring urges the contacting surface of the main body against the boneduring cutting.
 9. Surgical bone preparation instrument according toclaim 7, wherein: the cutting depth control ring comprises a proximalaxial surface having notches distributed circumferentially forpositioning according to various depths corresponding to the differentaxial lengths of the control ring, and the sliding body comprises aprotrusion adapted to insert in the notches of the proximal axialsurface to lock an angular position of the control ring under action ofthe spring.
 10. Surgical bone preparation instrument according to claim7, wherein the sliding body is arranged radially inside a cylindricalportion of the main body, wherein the contacting surface of the mainbody is arranged radially inside the cutting element, and wherein thesliding body comprises longitudinal slits receiving in sliding mannerattachment members of the main body which connect the contacting surfaceto the cylindrical portion.
 11. Surgical bone preparation instrumentaccording to claim 1, wherein the cutting element comprises a centralaperture through which the contacting surface of the main bodyprotrudes.
 12. Surgical bone preparation instrument according to claim1, wherein the sliding body can be dismounted from the main body. 13.Surgical bone preparation instrument according to claim 1, wherein theadjusted cutting depth is pre-planned.
 14. Surgical bone preparationinstrument according to claim 1, wherein the main body and the slidingbody comprise a bore for insertion of a reference pin adapted to befixed to the bone in order to guide the bone preparation instrument. 15.Surgical bone preparation assembly comprising the surgical bonepreparation instrument according to claim 1, wherein the surgical bonepreparation assembly comprises a patient-specific positioning tool forpositioning at least one reference pin on the bone.